In-Vitro investigation of anti-tumoral effects of metformin on osteosarcoma cells

Metformin, used in the treatment of type 2 diabetes mellitus (DM-II), has recently come to the forefront for its anti-tumoral properties, which enhance the effectiveness of adjuvant and neoadjuvant chemotherapy protocols. Studies have reported that these effects of metformin occur through different mechanisms, one of which is the mTORC1 signaling pathway. Multiple chemotherapy protocols are generally employed in the treatment of osteosarcoma cases, which often have an aggressive course. In our study, the anti-tumoral effects of metformin, when added to doxorubicin and cisplatin treatment, were investigated in MG-63 osteosarcoma cells. Cell counts and MTT assays were performed to determine the dosage and timing of metformin, doxorubicin, and cisplatin in single, dual, and triple combinations. Alkaline phosphatase (ALP) activities, which varied in response to anti-tumoral treatment, were measured in MG-63 osteosarcoma cells in the experimental groups. The migration capabilities of the cells were assessed using a wound healing (migration) assay, mTORC1 levels were analyzed by immunocytochemical staining, and ultrastructural changes were examined using transmission electron microscopy. As a result of dose and time determination experiments, effective doses were identified as 10 mM for metformin, 2.5 µM for cisplatin, and 1.5 µM for doxorubicin, with the effective duration set at 48 hours. It was found that metformin alone and in triple combination significantly inhibited MG-63 cell migration. In the experimental group where metformin was applied in combination with doxorubicin and cisplatin, decreases were observed in both ALP levels and mTORC1 levels. Ultrastructural examination revealed excessively dilated rough endoplasmic reticulum (RER) structures, mitochondrial damage, and lipit vacuoles in the experimental groups. Our study concludes that the combined application of metformin with doxorubicin and cisplatin increases in vitro anti-tumoral efficacy in MG-63 cells and may have clinical significance, particularly in preventing metastasis in the treatment of osteosarcoma.